The overall goal of the Program is to apply biochemical, cell biological, and transgenic and approaches to elucidate the important neurobiological activities of brain apolipoproteins relevant to Alzheimer disease (AD), especially apolipoprotein E (APOE, gene; apoE, protein) and apolipoprotein J (apoJ), and to clarify how beta-amyloidogenesis is regulated by these proteins. Since APOE epsilon4-related AD is the most prevalent form of AD, we plan to focus on identifying apoE-dependent (especially epsilon4-isoform-dependent) and apoJ-dependent phenomena which could become therapeutic targets. In Project 1, investigators will measure apoE-isoform/Abeta complex formation and Abeta fibrillogenesis in the absence or presence of non-denatured apoE epsilon 2, epsilon3 or epsilon4 [ROS], apoJ, ETC.) which are believed to contribute to beta-amyloidogenesis in vivo. The role of these phenomena will be determined after it is supplied in one of various physical states (soluble, aggregated/fibrilized, oxidized) to primary brain cultures or to brain in vivo in the absence or presence of either apoE epsilon 2, epsilon 3, or epsilon4 isoforms or apoJ (which, in turn, will be supplied either exogenously or via transgenesis). In Project 2, levels of circulating soluble obtained from normal subjects, elderly individuals and AD patients. sAbeta distribution among lipoprotein particles and the influence of apoE isoforms on sAbeta distribution will also be determined. Both non-oxidized and oxidized apolipoproteins will be studied. In relate aims, the cellular sites of clearance and degradation of circulating sAbeta Project 3, models of cerebral amyloid angiopathy will be created using novel as well as proven strategies. Also, constructing transgenic mice over-expressing the human betaAPP gene in neuronal cells, using the human betaAPP cDNA, containing the FAD K670N/M671L mutations, driven by murine Thy-1 promoter or the ARPP-21 neuronal specific core promoter. Finally, transgenic mice over-expressing the human apoL protein in glial cells using the glial fibrillary acidic protein promoter will be produced and used to determine the role of apoJ in the solubilization of Abeta. These Projects will be supported by an Administrative Core, a Histopathology Core, and an Abeta Core. The "Abeta Core" will oversee standardization of Abeta structural states and specialized, highly sensitive measurements of Abeta levels.